Use the arrow keys to control your movement. You have to avoid the red block but also jump on top of it to gain points. To attack the block jump over it and press the down arrow to slam downwards. If you go through the block's explosion you will still lose a life. If it is lagging too much on your computer try using phosphorus: https://phosphorus.github.io/#270875406 It's a little glitched but still works.
